def min(a, b):
    return a if a <= b else b

input_list = list(map(int,input().split()))
a, b, c, d = input_list

res = None
score_a= 100
score_b = 50
max_combo = a + b

if d * 100 >= 1000:
    res = 'Impossible'
else:
    set_combo = max_combo // 100
    res = 0
    
    for i in range(set_combo):
        reduce_b = min(b, 100)
        res += score_b * (2 ** i) * reduce_b
        b -= reduce_b
        
        reduce_a = 100 - reduce_b
        res += score_a * (2 ** i) * reduce_a
        a -= reduce_a
    res += (score_a * (2 ** set_combo) * a + score_b * (2 ** set_combo) * b)
    
print(res)